软件定义网络中基于负载均衡的多控制器部署算法

随着软件定义网络规模扩大，控制层与数据层解耦带来了诸如控制器部署等新问题。该文提出基于负载均衡的多控制器部署算法(Multi-Controller Deployment Algorithm Based on Load Balance, MCDALB)。算法首先根据网络拓扑结构及其负载情况，确定控制器数量K；然后根据控制器容量限制，提出一种近似比为2的多控制器负载均衡算法，将网络划分成K个控制区域；最后根据区域内所有交换机到控制器距离总和最小原则，在控制区域部署控制器。为了验证算法的性能，选取实际网络拓扑进行实验。实验结果表明，与AL, WL算法相比，该算法在满足控制器负载近似比为2的同时，网络最大延时差距不超过0.65 ms。

Multi-controller Deployment Algorithm Based on Load Balance in Software Defined Network

With the expansion of Software Defined Network (SDN), the decoupling of control layer and data layer brings new problems such as controller deployment. In this paper, a Multi-Controller Deployment Algorithm Based on Load Balance (MCDALB) in SDN is proposed. Firstly, the number, K, of controllers is determined based on network topology and its load. Secondly, according to the limitation of controller capacity, a multi-controller load balance algorithm with approximate ratio of 2 is proposed, which divides the network into K control regions. Lastly, the position of the controller in each region is selected, according to the minimum sum of all switch-to-controller distances in the region. In order to verify the performance of the proposed algorithm, the actual network topologies are applied. As to compare with the AL and WL algorithms, simulation results show that the proposed algorithm not only balances the controllers load, with an approximation ratio of 2, but also meets the maximum gap of network delay not more than 0.65 ms.